Metal propeller for aeroplanes, dirigibles, balloons, and the like



May 15, 1923.

T. MIDDLETON DIRIGIBLES BALLOONS AND THE LIKE METAL PROPELLER FOR AEROPLANES Filed Feb. 18 1921 Patent ay 15, 1923.

THOMAS MIDDLETON, F SCHENECTADY, NEW YORK.

METAL PROPELLER ron AEnorLANns, DIRIGIBLES, BALLOONS, AND THE LIKE.

Application filed February 18, 1921. Serial No. 446,001.

To all whom it may concern:

Be it known that I, THOMAS Mmnpn'roN, a citizen of the United States, residing at Schenectady, in the county ofSchenectady and State of New York, have invented cer;

tain new and useful Improvements in Metal Propellers for Aeroplanes, Dirigibles, Bal} loo'ns, and the like, of which the following U I gthe spot weld; and

is a. specification. v

This invention relates to propellers;

The primary object of the present lnvention residesin the production of a metal propeller for aeroplanes, dirigibles, balloons and other air machines.

Certain difficulties are.experienced 1n the manufacture of such sheet metal propellers as have been designed, in that the supporting frame work'arranged between the plates forming the blade'has not been-relatively proportioned, located or effectively secured It is an object of the present-invention to produce a propeller consisting of. metal sheets or plates shaped to form the contour of the blade and joined together by an interior support or framing of associated bracing ribs each proportioned, located and secured to the respective metal plates for effectivelysustaining the working pressure The present invention further contem plates the method of producing metal pro pellers which consists in spot Welding the metal sheets or plates at intervals to an interior support and further welding the edges of the plates, the relative close location of the spot welds together with the particular arrangement of accurately proportioned supporting or bracing elements. materially entering into the method of building up the propeller.

Another object gf theinvention is to pro; vide a .gnetal propeller having a flange formed on a portion of the respective blades:

thereby reducing the wind slip.

A further object of the invention is to pro- 4 vide a sheet metal propeller possessing advantages of perfect balance, lightness, durability and working efficiency as Well as comparative low cost in manufacture and repair.

Other objects will in' part be obvious;

In the accompanying drawings illustrating an embodiment of my invention for 'pur poses herein:

Fig. 1 is a face or proved propeller with shown;

Fig. 2 is a longitudinal section the line 2--2 of Fig. 1;

Fig. 3 is a transverse sectional View on the line 3-3 of Fig. l;

Fig. 4 1s a detail sectional view illustratplan view of-my imparts broken away as Fig. 5 is a detail perspective view showing a modlfied form of bracing rib..

hepresent invention has been designed to take the'place of the wooden propellers now used, se'rious difliculty often being experienced in boththemanufacture and use of the wooden'type of air screw. For example, the manufacture of wooden propel- 'lers depends largely upon skilled workmen who are required by tedious hand operationsand balance the blades.

tov carefully finish In use the climatic conditions of heat and moisture also affect the blades; and-when any of the blades are broken or injured the whole propeller is rendered useless and must be scrapped.

al view on It is to-overcome these difliculties that I,

have produced a metal propeller the construction of which duction, accuracy in shape and balance,- and readiness in repair, should one of the blades be injured.

permits of quantity pro;

Generally stated, the propeller comprises a plurality of blades each formed of metal plates or sheets jolned together by an interj mediate frame work of novel construction.

Each blade 'is secured to a hub section as will be understood, and is contour according to the requirements desired. The plates are preferably premed between .dies, the accuracy of WlllCh can be definitely obtained. Large quantities therefore of accurately formed lates can be produced as compared with t e highly skilled labor "required in the tedious manufacture of laminated wooden propellers. The supporting or reinforcing framework interposed between the plates can be also formed according to the desired'loc'ation' be tween the plates, andilarge quantities of these bracing elements can'.be inexpensively manufactured.

Referring to the drawings each blade of given the proper accurately v any tendency of Various formed of sheet metal plates the propeller is former for purposes herein 1 and 2, the

being designated the working face of the propeller and the latter constituting the back thereof. The plates are preferably of sheet steel but it will be'understood that other metals may be used. The inner ends of the sheets are serrated or notched to form the V-shaped portions 3 adapted to fit into M) on the hub of the propeller corresponding notches or serrations formed- (not shown). This construction of joint serves to prevent the sheet to rip or tear. forms of mating serrations or notches may be used. ()ther securing means,

,such as bolts, for example, are also provided for detachably afiixing the blades tothe hub as will be understood.

Provided on a portion of the edge of each blade is a flange a. This flange is formed as shown herein by bending an extending portion of one of the blades around the edge of by providing for lightness.

Fig. 1, although it ately according to its location between the plates, and slightly flared as at 6 for their more efiective positioning toward the outer end and side edges-of the blade.

Each rib is provided with a series of'openings 7 preferably elongated as shown, there These openings can be varied throughout the length of the rib and can be altered in size for accurately apportioning the weight of the blade and obtaining perfectbalance.

The preferred the ribs between the plates is best shown in will be understood that various changes in the positioning of the ribs may beresorted to without departing from the spirit of this invention. As shown the ribs are positioned substantially longitudinally of the blade; and in slightly spaced and daring relation to one another. The ends of the ribs are further flared-outwardly toward the sides and end of the blade, thereby carrying to the extreme outer edges a substantial degree of support or internal bracing.

An intermediate bracing or rib 8 is positioned across the outer end of the blade and serves to connect the outer reduced and flared ends of the ribs 5. This rib 8 may also be provided with openings 9 for furlocation or arrangement of ther increasing the. lightness of the blade, without, however, impairing its working strength.

The manner of associating the several foregoing parts in their relation one toward another constitutes a heretofore unknown method of producing metal propellers.

The present method of assembling and securing the sheet metal plates 1 and 2 to the ribs 5 involves a spot welding operation in. which the respective plates are welded at intervals to the ribs and further welded to each other at the edges. Thelocation of. the spot welds may be relatively close, the same being indicated by the numeral 9 in the detail Figure 4. They may be arranged al- I ternately upon each side of the rib or otherwise located with relation to the openings formed in the rib, or to each other. It is desirable to extend the spot welds throughout substantially the entire length of the rib, the intermediate portion of the ribs between the welds being in continuous contact with the inner opposedfaces of the plates 1 and 2. This association of ribs or braces with the inner opposed face of the sheets or plates forms a direct support between the plates throughout'the length of the ribs or bracing elements. It will be seen that the cross-sectional area of the rib together with its taper serves to insure this even and continuous contact with the opposite plates. A nicety of proportion in supporting strength. weight and balance can be obtained by the use of this relatively heavyand tapered rib.

In practice the ribs are arranged in associated relation with one of the plates of the blade and spot welded thereto by any one of the known welding processes. The electrical-process is preferred, although it will 195 be understood that other processes, for example the oXy-acetylene, or the thermic,as well as any other welding process, may be employed. 1 do not limit the invention to any particular process or apparatu hi h llo I may be used to edect the ,spot and other welding operations.

When one plate has been welded to one side of the bracing ribs, the-other plate is now placed in position and spot welded to' the opposite side of the ribs ln welding the plates and ribs together suitable supports or holding tables may be provided, and these together with suitable centering and locating devices serve to insure the correct and related positioning of the ribs and plates aswill be understood. The respective plates are also spot weldedto the connecting brace 8 which in turn may also be welded to the ribs between which it is inter- 125 posed v I The edges of the plates are now welded together in any suitable manner to comlete the blades. This weld may be a seam,

ap, spot, or other weld, and any processes ml hereinbefore mentioned may be 'used. If-

spot welded, the location of the welds is relatively close so as to insure a substantially continuous joint as will be understood.

When the wind slip flange 4 is formed in tegral with one of the metal sheets or plates, it is bent over and welded in any manner to the fac'eof the other plate, the extent of the lap being sufficient to insure an effective flange. If applied separately the flange may also be welded to the blade as will be understood. I,

In Fig. 5 a' hollow metallic supporting rib 10 is shown wherein'a series of openings can be provided in any one of its side walls for further lightening the structure.

While I have. shown four longitudinal and one transverse bracing elements, it will be understood that a greater or less number of each kind may be utilized, and I do not limit myself to either the number or the exact arrangement herein shown. Various shape propellers will necessitate different arrangements and relative positioning of the several parts and the disclosure herein Is for purposes of more clearly understanding the invention, reference being had to the following claims for ascertaining the definite limits of my invention.

I claim:

1. A propeller comprising relatively thin metal plates shaped to form the blades of the propeller, and a series of hollow tapered ribs interposed between the aforesaid plates and having their outer ends flared toward the opposite side edges of the plates for forming an interior support.

2. A propeller'comprising relatively thin metal plates shaped to form the blades of the ropeller, and a series of relativelythick liracing elements, each of said elements having all of its sides tapered to a point and shaped sothat their cross sectional area forms the direct support between the said plates throughout the length of the bracing elements.

3. A sheet metal propeller comprising relatively thin metal plates shaped to form the blades of the propeller, and an interior support formed of ribs extending in diverging directions from the hub. to the outer end and side edges respectively of the blade and arranged in continuous contact throughout their length with the aforesaid metal plates.

4. A sheet metal propeller comprising relatively thin metal plates shaped to form the blades of the propeller, and relatively thick bracing elements flaringly arranged between the plates and adapted to extend to the side and end edges thereof, said bracing'elements being shaped so that their cross sectional areas forms the direct support between the said plates throughout the length of the bracing element.

5. A sheet metal propeller comprising rel.- atively thin metal plates shaped to form the blades of the propeller, relativelythick and tapered bracing. elements fiaringly .arranged in continuous contact throughout their length with the aforesaid metal plates. and a relatively thin bracing element interposed betwcen the first mentioned bracing elements. v

6. A sheet metal propeller comprising relatively-thin metal plates shaped to form the oppos1te sides of the blades of the propeller, one of said plates having a projecting edge adapted to overlap a portion only. of the' other of said plates to form a wind slip retaining edge, the remaining edge portions of said plates being relatively smooth and adapted to form the air cleavage ed e.

7. The method of producing metallic propellers which consists in securing metal plates or sheets to the opposite sides of a supporting frame by spot welding the inner opposed faces of said sheets or plates to the outer sides of the supporting frame.

8. The method of producing metallic propellers which consists in securing relatively thin metal plates or sheets to a relatively heavy supporting frame by spot weldin the inner opposed faces of said plates or s 'eetsat intervals to the supporting frame.

9. The method of producing metallic propellers which consists in securing metal the respective edges of the plates or sheets to each othgr. v

10. Themethod of producing metallic propellers which consists in securing metal plates ing the inner faces of the plates or sheets to or sheets to an interior support by spot weld the support and seam welding the respective edges of the plates or sheets to each other.

11. The method of producing metallic propellers which consists in securing metal plates or sheets to a series of separate intenor supportsby spot welding' the faces of said sheets or plates at relatively close intervals to each support.

12. The method of producing metallic propellers which consists in securing metal plates or sheets rior supports by spot welding the faces of said sheets or plates at relatively close intervals to each support and seem welding to a series ofseparate, intethe edges of the respective plates or sheets to each other.

13. The method of producing metallic propellers which consists in spot welding the inner opposed faces of relatively thin metal sheets to the opposite outer sides of a series of separate supports. I v

14. The method of producing a metallic propeller blade which consists in spot weldmg the faces of thinmetal sheets, and further welding the edges thereof.

15. The method of producing a 'metallic propeller blade which consists in spot welding the inner opposed faces of thin metal sheets to spaced interior supports and secur ing the edges of the sheets to each other by further welding.

16. A sheet metal propeller comprising relatively thin metal plates shaped to form the blades of the propeller andhaving their inner hub ends interrupted by notches, serrations, or the like.

17. A metallic supporting rib for sheet metal propeller blades formed of a relatively heavy body portion comprising spaced 1ntegrally united side walls and a gradually tapered and light end portion.

18;. A metallic supporting rib for sheet metal propeller blades formed with a body portion of relatively thick metal and having a series of openings extending throughout said body portion and arranged at intervals therelin, and a tapered end of relatively thin meta 19. A hollow metallic supporting rib for sheet metal propeller blades formed of tapered side walls, all of said walls being1 tegrally united to each other throng out their length.

20. A hollow metallic supporting rib for sheet metal propeller blades having tapered 'side Walls integrally united to each other throughout their length and a series of openings formed in certain of said side walls.

In testimony whereofl affix my. signature.

THOMAS MIDDLETON. 

